1. Field of the Invention
The present invention relates to an optical semiconductor device having a distributed Bragg reflecting layer; specifically to an optical semiconductor device with little fluctuation in element properties and high quantum efficiency.
2. Background Art
A photodiode having a distributed Bragg reflector (DBR) layer between a light absorbing layer and a semiconductor substrate has been proposed. Transmitted light not absorbed in the light absorbing layer is reflected by the DBR layer, and is absorbed again in the light absorbing layer. Thereby, high quantum efficiency is obtained in a photodiode having a DBR layer (for example, refer to Japanese Patent Laid-Open No. 2003-318485).